Real-time full matrix capture with auto-focussing of known geometry through dual layered media

A full matrix capture technique is presented that allows for real-time imaging through a non-planar surface where the geometry is known. For an identified geometry the point of incidence at the refractive interface is calculated using Fermat’s principle and iterative techniques for each possible transducer position which is pre-processed ahead of the inspection. This information is combined with the transducer’s encoded position during the inspection process with post-processing of ultrasonic data performed over the graphic processing unit. This is shown to allow for rapid imaging of ultrasonic data by firstly reducing the need to auto-focus through the media, and secondly by exploiting the parallelisation power of the graphic card. To demonstrate this, a linear array transducer was mounted to a Perspex wedge where the technique was applied to generate ultrasonic imagery of side drilled holes through a curved surface. This is shown to offer significant performance over traditional full matrix imaging with low implementation and development costs.